MB90360 Series
14
4.
Precautions for when not using a sub-clock signal
If you do not connect pins X0A and X1A to an oscillator, use pull-down handling on the X0A pin and leave the
X1A pin open.
5.
Notes on during operation of PLL clock mode
If the PLL clock mode is selected, the microcontroller attempts to be working with the self-oscillating circuit even
when there is no external oscillator or external clock input is stopped. Performance of this operation, however,
cannot be guaranteed.
6.
Power supply pins (V
CC
/V
SS
)
If there are multiple V
CC
and V
SS
pins, from the point of view of device design, pins to be of the same potential
are connected the inside of the device to prevent such malfunctioning as latch up.
To reduce unnecessary radiation, prevent malfunctioning of the strobe signal due to the rise of ground level,
and observe the standard for total output current, be sure to connect the V
CC
and V
SS
pins to the power supply
and ground externally.
Connect V
CC
and V
SS
to the device from the current supply source at a low impedance.
As a measure against power supply noise, connect a capacitor of about 0.1
μ
F as a bypass capacitor between
V
CC
and V
SS
in the vicinity of V
CC
and V
SS
pins of the device.
7.
Pull-up/down resistors
The MB90360 Series does not support internal pull-up/down resistors (Port 2 : built-in pull-up resistors) . Use
external components where needed.
8.
Crystal oscillator circuit
Noises around X0 or X1 pin may be possible causes of abnormal operations. Make sure to provide bypass
capacitors via shortest distance from X0, X1 pins, crystal oscillator (or ceramic resonator) and ground lines, and
make sure, to the utmost effort, that lines of oscillation circuit do not cross the lines of other circuits.
It is highly recommended to provide a printed circuit board artwork surrounding X0 and X1 pins with a ground
area for stabilizing the operation.
9.
Turning-on sequence of power supply to A/D converter and analog inputs
Make sure to turn on the A/D converter power supply (AV
CC
and AVR) and analog inputs (AN0 to AN15) after
turning-on the digital power supply (V
CC
) .
Turn-off the digital power after turning off the A/D converter power supply and analog inputs. In this case, make
sure that the voltage does not exceed AVRH or AV
CC
(turning on/off the analog and digital power supplies
simultaneously is acceptable) .
V
CC
V
SS
V
CC
V
CC
V
CC
V
CC
V
SS
V
SS
V
SS
V
SS
MB90360
Series